Tuesday, February 21, 2006

Toxoplasmosis in California Sea Otters

I’ve always been fascinated by otters – all kinds of otters. One of my favourite books is “Ring of Bright Water” by Gavin Maxwell. Another otter book, “Tarka the Otter” written by Henry Williamson after World War I, which describes the adventures of an otter in North Devon, England, is on my bookshelf, too. My older son was captivated by Nathaniel Benchley’s “Oscar Otter,” and when he was three years old I had to read it to him over and over again.

The Arizona Sonora Desert Museum west of Tucson has a wonderful exhibit of river otters. You can watch them from above and also see them swimming through an underwater viewing window. It's one of my favourite places; I could watch them for hours.

When we camped on the California coast, I was introduced to sea otters. I loved their playfulness and the fascinating ways they adapt to the environment. Quite recently, I watched a documentary and saw a sea otter carefully wrapping itself in long strands of kelp to keep from floating away while it slept on the surface of the ocean. The Monterey Bay Aquarium’s web site includes a web cam of their sea otters.

So it was with great dismay that I read in BBC Web News last Sunday that Toxoplasma parasites are killing off sea otters, according to Patricia Conrad of the Wildlife Health Center at the University of California, Davis. Dr Conrad was speaking at the American Association for the Advancement of Science annual meeting in St Louis, Missouri.

According to Dr. Conrad, cat feces carrying the parasites wash into U.S. waterways. From there, the parasites travel to the sea where they infect the sea otters by causing deadly brain infections.

"What appears to be happening is that cats deposit their faeces - with the parasite - on land. When rainfall comes, it washes that into waterways and the fresh water takes it into the ocean." Once the parasite reaches the sea, it may be concentrated in mussels, oysters and clams, a major source of food for some otters. "For the sea otters, we don't exactly know how it gets in," said Dr Conrad, "but it must be through ingestion. "Because so many are dying, we are looking for things that concentrate the infection."

I'm also a cat lover, and I know how much cats love to hunt and prowl. However I believe it's definitely not a good idea to let them roam. Here in the desert, they can be taken by raptors, mountain lions, bobcats, or coyotes. And, as the article points out, they can fall victim to diseases when they hunt birds and small animals. Dr. Conrad is calling for owners to keep their cats indoors. She says:

“I know that's tough; I hate cleaning cat litter boxes as much as anybody. … But by keeping the cats indoors, we reduce the chance they're going to get infected by eating infected birds or rodents, and the chance they are going to shed their faeces outdoors."


lené said...

I lived in Santa Cruz for a while, and it remains one of the places closest to my heart. I loved watching the sea otters crack abalone on their chests and float in the rocky inlets. I had heard about this issue a year or two ago, but honestly, it had slipped my mind. I'm glad that they're still looking into the problem.

Thanks for listing the otter books too. I'm not familiar with any of them.

Pica said...

I work at the UC Davis Wildlife Health Center, where Dr. Conrad is affiliated. It was a complete surprise to find her mentioned here! She's a wonderful scientist and a wonderful human being.

We found four feral kittens outside our house last year. We kept two they are happy indoor kitties except we take them out on a leash every day so they can sniff and watch the jackrabbits...

Pam in Tucson said...

lene - I can only get my otter "fix" by going to the Desert Museum these days. I miss seeing them. I'll be following this issue to see what develops.

pica - Thanks so much for writing and letting me know about Dr. Conrad. I was so interested to read about her work and it's great to learn of a personal connection. How wonderful that you adopted two of the feral kittens and that they're happy on leashes. We had two cats in Brooklyn Heights in the late 50's and took them out on leashes, too, to walk along the Esplanade. There are too many feral cats in Tucson. There's a great program run by the Humane Society where people can donate money and bring them in to be spayed or neutered - that is, of course, if they can catch them. That helps a bit, but doesn't solve the whole problem.